A Study on the Corrosion Resistance of Cr-bearing Rebar in Mortar in Corrosive Environments Involving Chloride Attack and Carbonation

Abstract

Nine types of reinforcing steels having different Cr contents were placed in mortar simulating environments involving chloride attack, carbonation, and combined deterioration and subjected to corrosion-accelerating test for fundamental research on the corrosion resistance of Cr-bearing rebars in corrosive environments where reinforced concrete structures are to be constructed. The polarization resistance and corrosion potential of Cr-bearing rebars were then measured at temperatures of 60, 40, and 20°C to investigate their electrochemical properties in corrosive environments. Their corrosion area and average corrosion rate at the end of 40 cycles of corrosion-accelerating testing were also calculated to investigate their corrosion resistance.
As a result, the corrosion resistance of Cr-bearing rebars was found to increase as their Cr content increases in all corrosive environments, and the excellent corrosion resistance of Cr-bearing rebars with Cr contents of 5% or more and 7% or more was confirmed in uncarbonated and carbonated environments, respectively, with a chloride ion content of 1.2 kg/m³.